AES-128-CBC-HMAC-SHA256 ENCRYPTION TOOL
Other Crypto Algorithms
AES-128-CBC AES-128-CBC-CTS AES-128-CBC-HMAC-SHA1 AES-128-CBC-HMAC-SHA256 AES-128-CCM AES-128-CFB AES-128-CFB1 AES-128-CFB8 AES-128-CTR AES-128-ECB AES-128-GCM AES-128-GCM-SIV AES-128-OCB AES-128-OFB AES-128-SIV AES-128-WRAP AES-128-WRAP-INV AES-128-WRAP-PAD AES-128-WRAP-PAD-INV AES-128-XTS AES-192-CBC AES-192-CBC-CTS AES-192-CCM AES-192-CFB AES-192-CFB1 AES-192-CFB8 AES-192-CTR AES-192-ECB AES-192-GCM AES-192-GCM-SIV AES-192-OCB AES-192-OFB AES-192-SIV AES-192-WRAP AES-192-WRAP-INV AES-192-WRAP-PAD AES-192-WRAP-PAD-INV AES-256-CBC AES-256-CBC-CTS AES-256-CBC-HMAC-SHA1 AES-256-CBC-HMAC-SHA256 AES-256-CCM AES-256-CFB AES-256-CFB1 AES-256-CFB8 AES-256-CTR AES-256-ECB AES-256-GCM AES-256-GCM-SIV AES-256-OCB AES-256-OFB AES-256-SIV AES-256-WRAP AES-256-WRAP-INV AES-256-WRAP-PAD AES-256-WRAP-PAD-INV AES-256-XTS ARIA-128-CBC ARIA-128-CCM ARIA-128-CFB ARIA-128-CFB1 ARIA-128-CFB8 ARIA-128-CTR ARIA-128-ECB ARIA-128-GCM ARIA-128-OFB ARIA-192-CBC ARIA-192-CCM ARIA-192-CFB ARIA-192-CFB1 ARIA-192-CFB8 ARIA-192-CTR ARIA-192-ECB ARIA-192-GCM ARIA-192-OFB ARIA-256-CBC ARIA-256-CCM ARIA-256-CFB ARIA-256-CFB1 ARIA-256-CFB8 ARIA-256-CTR ARIA-256-ECB ARIA-256-GCM ARIA-256-OFB CAMELLIA-128-CBC CAMELLIA-128-CBC-CTS CAMELLIA-128-CFB CAMELLIA-128-CFB1 CAMELLIA-128-CFB8 CAMELLIA-128-CTR CAMELLIA-128-ECB CAMELLIA-128-OFB CAMELLIA-192-CBC CAMELLIA-192-CBC-CTS CAMELLIA-192-CFB CAMELLIA-192-CFB1 CAMELLIA-192-CFB8 CAMELLIA-192-CTR CAMELLIA-192-ECB CAMELLIA-192-OFB CAMELLIA-256-CBC CAMELLIA-256-CBC-CTS CAMELLIA-256-CFB CAMELLIA-256-CFB1 CAMELLIA-256-CFB8 CAMELLIA-256-CTR CAMELLIA-256-ECB CAMELLIA-256-OFB CHACHA20 CHACHA20-POLY1305 DES-EDE-CBC DES-EDE-CFB DES-EDE-ECB DES-EDE-OFB DES-EDE3-CBC DES-EDE3-CFB DES-EDE3-CFB1 DES-EDE3-CFB8 DES-EDE3-ECB DES-EDE3-OFB DES3-WRAPThe AES-128-CBC-HMAC-SHA256 algorithm combines symmetric encryption and message authentication to provide confidentiality and integrity for digital data. It integrates the Advanced Encryption Standard (AES) in Cipher Block Chaining (CBC) mode with a keyed-hash message authentication code (HMAC) using the SHA-256 hash function. The algorithm operates through distinct stages, each contributing to secure data handling.
Encryption Process
Initially, the algorithm generates a random 128-bit initialization vector (IV) to ensure that identical plaintext blocks produce different ciphertext blocks. The plaintext is divided into 128-bit blocks and processed sequentially. Each block is XORed with the previous ciphertext block, or the IV for the first block, before undergoing AES encryption with a 128-bit symmetric key. The use of CBC mode ensures that patterns in the plaintext are obscured, enhancing security against block-level analysis.
Message Authentication
Following encryption, the algorithm computes an HMAC using SHA-256. The HMAC is generated over the concatenation of the IV and the ciphertext to protect both components against modification. A separate key for HMAC computation is typically derived from the original symmetric key or provided independently. This keyed-hash ensures that any alteration of the ciphertext or IV can be detected during verification, maintaining data integrity.
Key Management
Proper key management is critical. The symmetric encryption key and the HMAC key must be generated securely, stored, and transmitted using protected channels. Compromise of either key can lead to exposure of plaintext data or unauthorized modification of messages. AES-128 requires a 128-bit key, while HMAC-SHA256 benefits from a key of sufficient length, commonly 256 bits, to prevent brute-force attacks.
Decryption and Verification
Decryption reverses the encryption process. The receiver first verifies the HMAC using the same SHA-256 procedure to confirm message integrity. Only if the HMAC matches is the ciphertext decrypted block by block using AES-128 in CBC mode. The IV is applied for the first block and subsequent blocks are processed using the CBC chaining method. Successful verification guarantees both authenticity and confidentiality of the transmitted data.
Security Considerations
This combined approach provides robust protection against common attack vectors. AES-128-CBC ensures confidentiality through strong symmetric encryption, while HMAC-SHA256 provides integrity and authenticity assurances. Correct implementation requires attention to padding schemes, IV generation, key separation, and resistance to timing attacks to maintain overall security. The algorithm is widely used in secure communications, encrypted storage, and cryptographic protocols.